Linked Life Data

1708337

Source:http://linkedlifedata.com/resource/pubmed/id/1708337

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1991-5-24
pubmed:abstractText
Insulin-like growth factors (IGF-I and IGF-II) are endocrine and autocrine factors affecting bone growth and metabolism. Binding proteins for IGFs (IGFBPs) are synthesized by the target tissues of IGF actions. Thus, IGFBPs may act as modulators for the biological functions of IGFs. We have characterized the rat IGFBPs (rIGFBPs) and studied their regulation by 17 beta-estradiol (beta E2) and human GH (hGH) in rat osteoblast-like (ROB) cell cultures. ROB cells were prepared from 19- to 20-day fetal rat calvariae by sequential collagenase digestion and studies were performed on the serum and phenol red-free conditioned medium of confluent cultures. [125I]IGF-I ligand blots showed that the major rIGFBP in the ROB is a nonglycosylated protein of 31 kilodaltons. This protein was immunoprecipitated by a specific antibody to rIGFBP-2 and messenger RNA for rIGFBP-2 was detected by RNA hybridization indicating that the rIGFBP-2 is the major rIGFBP of ROB. A minor band at 24 kilodaltons is likely to be the rat homologue of the newly isolated inhibitory IGFBP-4. The predominant glycosylated adult form of rIGFBPs of rat serum, rIGFBP-3, was undetectable. When cultures were treated with beta E2 for 2 days, there was a dose-dependent biphasic response which showed an inhibition of the rIGFBP-2 at low doses of 10(-11) to 10(-9) M and a stimulation at 10(-6) M. These changes in rIGFBP-2 parallel the changes in the endogenous IGF-I level. rIGFBP-2 level was not affected by 17 alpha-estradiol at the same concentration range. hGH, on the other hand stimulated the levels of rIGFBP-2 and rIGFBP-4 at doses ranging from 10(-11) to 10(-9) M without changing the IGF-I secretion. The alteration of the rIGFBPs by beta E2 and hGH suggests a role for these hormones in bone by modulating the biological functions of IGFs via their binding proteins.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0013-7227
pubmed:author
pubmed:issnType
Print
pubmed:volume
128
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2489-96
pubmed:dateRevised
2004-11-17
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Further characterization of insulin-like-growth factor binding proteins in rat osteoblast-like cell cultures: modulation by 17 beta-estradiol and human growth hormone.
pubmed:affiliation
Department of Developmental Biology, Genentech, Inc., South San Francisco, California 94080.
pubmed:publicationType
Journal Article